Tip prefetching: dealing with the bit rate variability of video streams

The bit rate variability of video streams is a difficult obstacle to achieve an efficient VOD server. It is a nuisance especially for deterministic systems, where resources are reserved to guarantee quality of service. We propose a novel way to deal with this called tip prefetching. Its main idea is prefetching parts of the largest blocks in the buffer levelling the amount of data being read from disks in each round. We also suggest a performance model, a method for deciding the prefetching horizon, and an adaptive scheme which adjusts the prefetching horizon according to the condition of the system. Our simulation results show that tip prefetching services up to 81% more streams with the saved resource. Tip prefetching is a simple but powerful technique for deterministic VOD system servicing VBR streams.